“Processed food” is a category I’ve historically filed alongside alcohol and gluten under “things I know I’m not supposed to eat but do anyway.” I know this sounds nuts, but for years, I found nothing intrinsically terrifying about eating a frozen curry bowl for dinner, followed by two soft-baked Chips Ahoy! cookies that tasted chewy and delicious, despite having been in my cupboard since 2009. I never thought about what it took to make these foods possible. Why ruin the illusion? They miraculously eliminated the need to cook. Plus, 400 “processed” calories had to be better than 1000 non-processed ones, right?
This was my mindset until late last year, when I listened to a podcast that cracked my blissful ignorance about processed food wide open. The episode, called "War & Pizza" from 99% Invisible, reported that the technology behind the “instant” foods many of us busy modern people depend on—boxed cereals, granola bars, TV dinners (even the fancy $7 ones)—was first introduced in the 1950s. After World War II, the U.S. government realized it needed a better way to preserve soldiers’ rations while they were at war, without access to refrigerators and cooking equipment.
So, after some time in the lab, shelf-stable, no-cook meals were born. Eventually, they made their way into American kitchens—“thanks to Madison Avenue marketing and suggestions that housewives were too busy to cook,” explains certified nutritionist Dana James. “Anyone remember processed mashed potatoes? My grandma used to make them—just add milk, and voilà! Processed food has grown steadily since then.”
The idea of eating what was essentially glorified military food made the hairs on the back of my neck stick straight up. Of course cookies and pizza weren’t supposed to taste soft and scrumptious after lying around for half a decade. These foods weren’t invented with regular people in mind.
So I vowed to swear off processed foods forever. That is, until I realized that bread, pasta, almond milk, frozen fruit, and many other healthy staples of my diet are technically processed.
This made me wonder: Are TV dinners and Cheetos “processed” in the same way fresh-baked bread and tofu are? And what effects do these types of processing have on our bodies? Do I need to give up processed food altogether to be healthy?
To get answers, I spoke to four top nutrition experts. For the end-all, be-all truth about processed foods, keep scrolling.
Here’s the thing: There’s no official definition of "processed." According to James, "It can include anything from a Twinkie to a green juice in a bottle." But for simplicity, you can think of it as any food that’s been purposefully modified to make it longer-lasting or easier to use. This is obviously a broad category, and can include processes as benign as freezing fresh vegetables or as involved as formulating instant curry from artificial ingredients in a factory.
However, there is a major difference in nutrition between foods that are processed and foods that are hyper-processed. “Processed food often gets a bad reputation, because we get caught up in the word processed without realizing what it really means,” says Alexandra Miller, corporate dietitian at Medifast. “Processed foods fall on a spectrum.”
To break it down: You have your minimally processed foods that were simply prepped for convenience, like chopped vegetables and roasted nuts. There are foods that were processed at their peak freshness to ensure nutritional quality and tastiness, like canned beans and frozen fruits. “Items such as cake mix or jarred tomato sauce that have ingredients added for flavor, texture, and freshness are next on the processed food spectrum,” says Miller. Packaged snacks (from Funyuns to Wonder Bread), frozen meals, and processed meats like bacon and salami fall under the category of hyper-processed.
Let’s define “hyper-processed” a little better. “A recent study in The British Medical Journal defines hyper-processed foods as those that are formulations of several ingredients that, besides sugar, oil, salt, and fat, are not generally used in cooking,” says registered dietitian Rachel Berman, head of content for About.com Health. You can recognize these foods because of their long ingredient lists and packages with “shiny labels and logos,” adds Harvard Medical School research fellow Rachele Pojednic, EdM, Ph.D. “The purpose is to have long-lasting, convenient, highly palatable, ready-to-eat or drink products.”
Most of us know that Cheetos and Kraft mac ’n’ cheese aren’t healthy choices. But even foods marketed as “health products” can be hyper-processed. Think “diet” ice cream bars, “high-protein cereal,” and “gluten-free crackers,” says James. Don’t be fooled by these foods. “Processing takes out the nutrients and replaces it with convenience,” James says.
With different levels of food processing come different effects on the body. I often think of frozen fruit and bagged spinach as less nutritious than the fresh kind, but Miller says these foods “have simply been prepped for convenience, which is a great way to ensure that they are a regular component of your meals and snacks.” So if the choice is between frozen strawberries or no strawberries at all, always choose frozen.
Other minimally processed foods like canned chickpeas and fresh bread have short, recognizable ingredient lists and should also be considered healthy, says James. And according to Pojednic, the type of processing used to make tofu is more akin to cooking, and shouldn’t be feared or avoided.
However, hyper-processed foods like breakfast bars and instant noodles can have a number of negative effects on your health. These foods introduce foreign chemicals to the body, says James. Plus, they contain very few nutrients. “To metabolize them, you need B vitamins, iron, zinc, and magnesium, and the hyper-processed foods don't contain any of these nutrients, so in effect, they steal your own supply just so they can be metabolized,” she says. “They are like the bad boyfriend that seduces you, then gives you nothing in return.”
In addition, many processed foods contain more sugars, salt, and fat than you realize. These ingredients are added to prolong shelf life, provide structure, and improve taste, says Miller, and you won’t find them simply by quickly glancing at the calorie count. These ingredients are known to cause weight gain, diabetes, hormonal imbalances, and a slew of other chronic diseases. “Some studies have also shown that eating a large amount of processed meat may be linked to a higher risk of cancer and heart disease,” adds Miller.
What’s important to remember is that you can determine how “healthy” a processed food is by looking at its starting ingredients. “If you begin with vegetables or grains, you are going to end up with a healthier product,” says Pojednic. “If you begin with sugar, salt, fat, and chemicals, not so much.”
A year ago, I thought processed food was the best thing that ever happened to humankind. Six months ago, I decided it was the devil’s work. But according to our nutrition experts, neither of these attitudes gets it quite right.
“It’s okay to have a some hyper-processed food occasionally,” says James. “Your body is very robust and you’ll survive [the day] at a friend’s place who doesn’t have the same wellness ethics as you.” In other words, if all there is to eat is salami sandwiches and chips, you’ll live.
But all in all, a good rule to live by is this: “If more than 20% of your meals come from a packet, your diet is too processed,” says James. Look for ways to replace those hyper-processed foods with fresh, equally convenient choices. Grab a banana instead of a Chewy bar; mix up a fruit smoothie instead of a guzzling a Diet Coke.
After all, our kitchens aren’t battlefields. We have the resources we need for healthy eating. But the rest is up to us.
Want to learn more about processed foods? Check out Pandora's Lunchbox: How Processed Food Took Over the American Meal ($13).